A typical flooded lead-acid battery includes positive and negative electrodes and an electrolyte. The electrodes include grids, which are primarily constructed of lead, are often alloyed with antimony, calcium, or tin to improve their mechanical characteristics. Antimony is generally a preferred alloying material for grids in deep discharge batteries.
In a flooded lead-acid battery, positive and negative active material pastes are added to positive and negative electrode grids, respectively, forming positive and negative electrodes. The positive and negative active material pastes generally comprise lead oxide (PbO or lead (II) oxide.) The electrolyte typically includes an aqueous acid solution, most commonly sulfuric acid. Each of the electrodes includes a lug, e.g., a tab extending up therefrom. Lugs of the positive electrodes are connected via a positive strap, and lugs of the negative electrodes are connected via a negative strap. Once the battery is assembled, the battery undergoes a formation step in which a charge is applied to the battery in order to convert the lead oxide of the positive electrodes to lead dioxide (PbO2 or lead (IV) oxide) and the lead oxide of the negative electrodes to lead.
After the formation step, a battery may be repeatedly discharged and charged in operation. During battery discharge, the positive and negative active materials react with the sulfuric acid of the electrolyte to form lead (II) sulfate (PbSO4). By the reaction of the sulfuric acid with the positive and negative active materials, a portion of the sulfuric acid of the electrolyte is consumed. However, the sulfuric acid returns to the electrolyte upon battery charging. The reaction of the positive and negative active materials with the sulfuric acid of the electrolyte during discharge may be represented by the following formulae.Pb(s)+SO42−(aq)PbSO4(s)+2e−  Reaction at the negative electrode:PbO2(s)+SO42−(aq)+4H++2e−PbSO4(s)+2(H2O)(l)  Reaction at the positive electrode:As shown by these formulae, during discharge, electrical energy is generated, making the flooded lead-acid battery a suitable power source for many applications. For example, flooded lead-acid batteries may be used as power sources for, electric vehicles such as forklifts, golf cars, electric cars, and hybrid cars. Flooded lead-acid batteries are also used for emergency or standby power supplies, or to store power generated by photovoltaic systems.
As a result of repeated charge and discharge, active material can build up on top of the negative electrodes. This buildup is referred to as “moss” with the phenomenon referred to as “mossing.” When excessive mossing occurs, it can create a short between the negative electrodes and the positive strap. Accordingly, moss guards are often used in lead-acid batteries to physically prevent the active material building up on top of the negative electrodes from touching the positive strap. Moss guards are made of a semi-flexible material and generally include a body and a plurality of fingers extending from each side of the body. While moss guards are generally only needed between the negative electrodes and the positive strap, in order to secure the moss guards, a plurality of fingers extend from each side of the body portion, thereby securing the moss guard between the positive lugs, on one side, and the negative lugs, on the other side.
However, inserting traditional moss guards into a battery cell can be time consuming and difficult. That is, because the moss guards are made to be secured between the two sets of lugs, they must be bent or folded so that both sides can be inserted. In bending and inserting the moss guards, the separators can be damaged as the fingers are forced in between the plates. As such, traditional moss guards can be time consuming to use and can also damage the battery cells.